Caspases comprise a family of cysteine protease enzymes with a well-known role as key mediators in apoptosis signaling pathways and cell disassembly. Interleukin converting enzyme (ICE), also known as Caspase-1, was the first identified caspase. In humans, 11 other known caspases have been further identified. Caspases have been classified in two general groups according to their effects: proapoptotic (caspase-2, 3, 6, 7, 8, 9, 10) and proinflammatory (caspase-1, 4, 5, 11, 12) caspases. The proapoptotic caspases have been divided in initiators (caspase-2, 8, 9, 10) also known as group II, and executioners (caspase-3, 6, 7) of the apoptotic process or group III. The Interleukin converting enzyme (ICE) also known as Caspase-1 has a proinflammatory role only.
There is growing evidence demonstrating the role of caspases in very diverse pathologies. For instance it is known that proapoptotic caspases are involved in the pathogenesis of many cardiovascular disorders. Some proapoptotic caspases such as caspase-8 also possess non-apoptotic function that may contribute to tumor progression. Caspase-1 plays an important role in response to pathogenic infection as well as in inflammatory and autoimmune disorders. In addition, caspase-1 activity is increased in retinas of diabetic patients and it constitutes a critical regulator of cardiomyocyte programmed cell death in the mammalian heart. Caspases also plays a role in neurodegenerative diseases and trauma. For instance, it has been shown that the caspase-3 cascade is highly activated due to the traumatic spinal cord injury. Finally, the activation of caspase-1 and caspase-3 in Amyotrophic Lateral Sclerosis (ALS) patients and the activation of caspase-7, -8, and -9 in a mouse model at end stage of ALS have been reported. Increased levels of apoptosis and caspase activity (especially caspase-3) are reported to be frequently observed at sites of cellular damage in both acute (e.g. Sepsis, myocardial infarction (MI), Ischemic Stroke, Spinal cord injury (SCI), traumatic Brain Injury (TBI)) and neurodegenerative disease (e.g. Alzheimer's, Parkinson's and Huntington's diseases, and multiple sclerosis (MS)).
Since caspases are involved in a number of diseases, several compounds and methods have been developed to inactivate them. For example, the broad irreversible caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (z-VAD-fmk) was protective and efficiently blocked death receptor-mediated liver injury in animal models (Rodriguez et al. (1996), J Exp Med. 1996 Nov. 1; 184(5):2067-72). Myocardial infarction and the resulting death of myocytes was ameliorated by z-VAD-fmk and related peptide inhibitors in animal models (Yaoita et al., 91998) Circulation 97: 276-281). There have been also a lot of efforts for identifying inhibitors of peptidase. For instance, Hanzlik and Thompson (J. Med. Chem. (1984), 27(6), 711-712) describe vinylogous amino acid esters for inactivating thiol proteases. Thompson et al. (J. Med. Chem. (1986), 29(1), 104-111) describe carboxyl-modified amino acids and peptides as protease inhibitors. Liu and Hanzlik have prepared a series of peptidyl Michael acceptors with different electron withdrawing groups with different recognition and binding groups as inactivators against papain, a member of the cysteine proteinase family. Similarly, U.S. Pat. Nos. 5,976,858 and 6,287,840 to Palmer wt et al. describes irreversible cysteine protease inhibitors containing vinyl groups conjugated to electron withdrawing groups. However, these and other compounds are not effective against caspases, because caspases are among the most specific endopeptidases.
Given their role in several diseases and conditions, there is a need for compounds capable of selectively targeting either a specific caspase or a group of caspases. There is also a need for effective pharmaceutical compositions and method of treatment for caspase-related diseases.
The present invention addresses these needs for novel therapies, new treatment methods, compounds, and pharmaceutical compositions.
Additional features of the invention will be apparent from review of the disclosure, figures and description of the invention below.